1. Field of the Invention
The present invention relates to a buckstay connecting system, and more particularly, to a buckstay connecting system for connecting a vertical buckstay installed in a height direction of a furnace with a horizontal buckstay installed in a width direction of the furnace.
This application claims priority to and the benefits of Japanese Patent Application No. 2009-243278 filed on Oct. 22, 2009, the disclosure of which is incorporated herein by reference.
2. Background Art
As is widely known, furnaces installed on, for example, thermal electric power plants have a furnace wall made up of a plurality of water pipes and fins interposed between the water pipes.
The furnace wall is supported in such a way that it is suspended from a building covering to build a furnace, and thus has weak stiffness. For this reason, in order to enhance the stiffness of the furnace wall and to inhibit the furnace from being greatly deformed by thermal expansion of the furnace wall or pressure variation in the furnace, a plurality of buckstays are disposed around the furnace.
These buckstays are made up of horizontal buckstays horizontally installed along the furnace wall around the furnace and vertical buckstays vertically installed along the furnace wall around the furnace. Each buckstay is formed of, for example, H-section steel.    [Patent Document 1] Japanese Patent Application Publication No. 2001-221404
However, the buckstays prevent excessive deformation of the furnace, but fail to perfectly inhibit such deformation. As such, when the furnace is deformed by thermal expansion, this leads to displacement of the buckstays.
The buckstays are typically made up of vertical buckstays installed in a height direction of the furnace and horizontal buckstays installed in a width direction of the furnace. Although these vertical and horizontal buckstays are interconnected, the vertical buckstays are displaced in a vertical direction with respect to the horizontal buckstays due to the above-mentioned deformation of the furnace. For this reason, the vertical buckstays are connected to be able to slide in the vertical direction with respect to the horizontal buckstays.
In greater detail, the horizontal buckstays are installed in multiple steps in the height direction of the furnace, and the vertical buckstays are installed between the multiple steps. Each vertical buckstay is welded and fixed to the horizontal buckstay disposed just above an upper end thereof and is inserted into a box-shaped socket part installed on the horizontal buckstay disposed just below a lower portion including a lower end thereof. Here, the lower end of the vertical buckstay is not fixed to the horizontal buckstay but is only inserted into the socket part. Thus, when the vertical buckstay is displaced in the vertical direction with respect to the horizontal buckstay, the vertical buckstay slides in the vertical direction with respect to the horizontal buckstay.
In this manner, the vertical buckstay slides in the vertical direction with respect to the horizontal buckstay, but its lower end is always located in the socket part. As such, the vertical buckstay can always come into contact with the surface of an inner wall of the socket part. Thereby, the horizontal buckstay is prevented from falling.
During construction of thermal electric power plants, or the like, when these buckstays are installed around the furnace, the horizontal buckstays are first installed, and then the vertical buckstays are installed between the horizontal buckstays. However, since it is necessary to inhibit the falling of the horizontal buckstays until the upper ends of the vertical buckstays functioning to prevent the horizontal buckstays from falling are welded to their upper horizontal buckstays and the lower portion of the vertical buckstays are inserted into the socket parts installed on their lower horizontal buckstays, temporary construction materials supporting the horizontal buckstays are installed around the furnace. Since these temporary construction materials need to support all the horizontal buckstays ready to fall in a horizontal state, too many construction materials are required. Further, after all of the vertical buckstays are installed, all of the temporary construction materials need to be removed. As such, the temporary construction materials for supporting the horizontal buckstays are attributed to increasing the period and cost of construction when constructing, for example, the thermal electric power plant.
Further, when the vertical buckstays are installed in a construction field, the upper ends of the vertical buckstays are welded to the horizontal buckstays, and then socket parts are welded to the horizontal buckstays so as to surround the lower portion of the vertical buckstays. For this reason, the welding work is great in the construction field, which leads to increasing the period and cost of construction.